[PATCH 3.2 37/77] drm/ttm: Fixed a read/write lock imbalance

Ben Hutchings
2015-12-24T15:43:55Z

From: Thomas Hellstrom <thellstrom@vmware.com>

commit 025af189fb44250206dd8a32fa4a682392af3301 upstream.

In ttm_write_lock(), the uninterruptible path should call
__ttm_write_lock() not __ttm_read_lock(). This fixes a vmwgfx hang
on F23 start up.

syeh: Extracted this from one of Thomas' internal patches.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/gpu/drm/ttm/ttm_lock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/ttm/ttm_lock.c
+++ b/drivers/gpu/drm/ttm/ttm_lock.c
@@ -180,7 +180,7 @@ int ttm_write_lock(struct ttm_lock *lock
spin_unlock(&lock->lock);
}
} else
- wait_event(lock->queue, __ttm_read_lock(lock));
+ wait_event(lock->queue, __ttm_write_lock(lock));

return ret;
}